A century old medical technique may provide a major opportunity to infertile couples to become a parent, and that too without needing the In-Vitro Fertilisation technique, researchers say.

The technique, known as hysterosalpingography (HSG), is a dye test of the fallopian tubes conducted under X-ray, and involves flushing the woman's fallopian tubes with an iodised poppy seed oil.

It was first carried out in 1917, but since the 1950s both water-based and oil-based solutions was used.

"Over the past century, pregnancy rates among infertile women reportedly increased after their tubes had been flushed with either water or oil during this X-ray procedure. Until now, it has been unclear whether the type of solution used in the procedure was influencing the change in fertility," said Ben Mol, professor at the University of Adelaide.

The study, published in the New England Journal of Medicine, showed clear benefits of oil-based solution, with nearly 40 per cent of infertile women achieving successful pregnancies within six months after the treatment as compared to 29 per cent of infertile women in the water group.

The procedure was found to be beneficial in particular for women who do not have any other treatable fertility symptoms, the researchers said.

"The rates of successful pregnancy were significantly higher in the oil-based group, and after only one treatment. This is an important outcome for women who would have had no other course of action other than to seek IVF treatment. It offers new hope to infertile couples," Mol stated.

The treatment comes without any known side-effects and also costs just a fraction of one cycle of IVF.

For the study, the team compared the benefits of flushing the fallopian tubes with either an oil-based or water-based solution in 1,119 women.